#!/usr/bin/env bash

# Copyright (C) 2016 Paul Kocialkowski <contact@paulk.fr>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

BUILD_SYSTEM="libreboot"

PROJECTS="projects"
SOURCES="sources"
BUILD="build"
INSTALL="install"
RELEASE="release"
SYSTEMS="systems"
IMAGES="images"
TOOLS="tools"

CONFIGS="configs"
PATCHES="patches"
TARGETS="targets"
REVISION="revision"
BLOBS="blobs"
BLOBS_IGNORE="blobs-ignore"
BLOBS_DISCOVER="blobs-discover"

DOTEPOCH=".epoch"
DOTRNDSEED=".rndseed"
DOTVERSION=".version"
DOTREVISION=".revision"
DOTTARFILES=".tarfiles"
ARCHIVE="tar.xz"
CHECKSUM="sha256sum"
DSIG="asc"

function_check() {
	local function=$1

	declare -f -F "$function" > /dev/null
}

variable_check() {
	local variable=$1

	test ! -z "${!variable}"
}

arguments_list() {
	local argument

	for argument in "$@"
	do
		printf '%s\n' "$argument"
	done
}

download_wrapper() {
	local download_dir="$1"
	shift
	local uris=($@)

	# TODO: Add support for curl, in addition
	# to wget, for compatibility reasons
	wget_options=(
		--config=/dev/null
		--secure-protocol=PFS
		--directory-prefix="${download_dir}"
		--continue
		--
	)

	wget "${wget_options[@]}" "${uris[@]}"
}

diff_patch_file() {
	local repository_path="$1"
	local patch_file_path="$2"

	# TODO: Improve handling of filenames to avoid gotchas w/ \n, \t, etc.
	local filename_in_diff="$(sed -rne 's/^-{3}\s+([^ 	\r\n]*).*/\1/p' "${patch_file_path}")"

	local source_file_path

	if ! ( grep -E '^-{3}.*/' "${patch_file_path}" >/dev/null 2>&1 ); then
		source_file_path="${repository_path}/${filename_in_diff}"
	else
		source_file_path="${repository_path}/${filename_in_diff##*/}"
	fi

	patch "${source_file_path}" "${patch_file_path}"
}

path_wildcard_expand() {
	local path=$@

	# Evaluation fails with unescaped whitespaces.
	path=$( printf '%s\n' "$path" | sed "s/ /\\\ /g" )

	eval "arguments_list "$path""
}

file_checksum_create() {
	local path=$1

	local checksum_path="$path.$CHECKSUM"
	local name=$( basename "$path" )
	local directory_path=$( dirname "$path" )

	(
		cd "$directory_path"
		sha256sum "$name" > "$checksum_path"
	)
}

file_checksum_check() {
	local path=$1

	local checksum_path="$path.$CHECKSUM"
	local name=$( basename "$path" )
	local directory_path=$( dirname "$path" )

	if ! [ -f "$checksum_path" ]
	then
		printf '%s\n' 'Could not verify file checksum!' >&2
		return 1
	fi

	(
		cd "$directory_path"
		sha256sum -c "$checksum_path"
	)
}

file_signature_create() {
	local path=$1

	local signature_path="$path.$DSIG"

	if [ -z "$RELEASE_KEY" ]
	then
		return 0
	fi

	gpg --default-key "$RELEASE_KEY" --armor --output "$signature_path" --detach-sign --yes "$path"
}

file_signature_check() {
	local path=$1

	local signature_path="$path.$DSIG"

	if ! [ -f "$signature_path" ]
	then
		printf '%s\n' 'Could not verify file signature!' >&2
		return 1
	fi

	gpg --armor --verify "$signature_path" "$path"
}

file_verification_create() {
	local path=$1

	file_checksum_create "$path"
	file_signature_create "$path"
}

file_verification_check() {
	local path=$1

	file_checksum_check "$path"
	file_signature_check "$path"
}

file_exists_check() {
	local path=$1

	test -f "$path"
}

directory_filled_check() {
	local path=$1

	if [ -z "$( ls -A "$path" 2> /dev/null )" ]
	then
		return 1
	else
		return 0
	fi
}

archive_files_create() {
	local source_path="$1"

	local directory="$(basename "${source_path}")"
	local tarfiles_path="${source_path}/${DOTTARFILES}"
	local revision_path="${source_path}/${DOTREVISION}"
	local version_path="${source_path}/${DOTVERSION}"
	local epoch_path="${source_path}/${DOTEPOCH}"
	local rnd_seed_path="${source_path}/${DOTRNDSEED}"

	# Files in "${tarfiles_path}" are NUL terminated.
	# `tr '\0' '\n'` for human-readable output.
	if git_check "${source_path}"; then
		git_files "${source_path}" > "${tarfiles_path}"
		printf '%s\0' "${DOTTARFILES}" >> "${tarfiles_path}"
	else
		find "${source_path}" -print0 | env LC_ALL='C.UTF-8' sort -z | sed -z "1d;s,^${source_path}/\\?,,;/^${DOTTARFILES}\$/d" > "${tarfiles_path}"
	fi

	for dotfile in "${revision_path}" \
			"${version_path}" \
			"${epoch_path}" \
			"${rnd_seed_path}"
	do
		if [[ -f "${dotfile}" ]]; then
			printf '%s\0' ".${dotfile##*.}" >> "${tarfiles_path}"
		fi
	done
}

archive_files_date() {
	local source_path="$1"

	local epoch_path="${source_path}/${DOTEPOCH}"

	if [[ -n "${SOURCE_DATE_EPOCH}" ]]; then
		find "${source_path}" -execdir touch --no-dereference --date="@${SOURCE_DATE_EPOCH}" {} +
	fi
}

archive_create() {
	local archive_path="$1"
	local source_path="$2"
	local directory="$3"

	local tarfiles_path="${source_path}/${DOTTARFILES}"
	local directory_path="$(dirname "${archive_path}")"

	mkdir -p "${directory_path}"

	if [[ -z "${directory}" ]]; then
		directory="$(basename "${source_path}")"
	fi

	archive_files_create "${source_path}"
	archive_files_date "${source_path}"

	local tar_options=(
		--create
		--xz
		--file="${archive_path}"
		--files-from="${tarfiles_path}"
		--transform="s,^,${directory}/,S"
		--no-recursion
		--null
		--owner=0
		--group=0
		--numeric-owner
	)

	(
		cd "${source_path}"
		tar "${tar_options[@]}"
	)
}

archive_extract() {
	local archive_path="$1"
	local destination_path="$2"

	if [[ -z "${destination_path}" ]]; then
		destination_path="$(dirname "${archive_path}")"
	fi

	tar -xf "${archive_path}" -ps -C "${destination_path}"
}

rootfs_files_create() {
	local source_path="$1"

	local directory="$(basename "${source_path}")"
	local tarfiles_path="${source_path}/${DOTTARFILES}"

	# Files in "${tarfiles_path}" are NUL terminated.
	# `tr '\0' '\n'` for human-readable output.
	execute_root find "${source_path}" -print0 | env LC_ALL='C.UTF-8' sort -z | sed -z "1d;s,^${source_path}/\\?,,;/^${DOTTARFILES}\$/d" > "${tarfiles_path}"
}

rootfs_files_date() {
	local source_path="$1"

	local epoch_path="${source_path}/${DOTEPOCH}"

	if [[ -n "${SOURCE_DATE_EPOCH}" ]]; then
		execute_root find "${source_path}" -execdir touch --no-dereference --date="@${SOURCE_DATE_EPOCH}" {} +
	fi
}

rootfs_create() {
	local rootfs_path="$1"
	local source_path="$2"
	local directory="$3"

	local tarfiles_path="${source_path}/${DOTTARFILES}"
	local directory_path="$(dirname "${rootfs_path}")"

	mkdir -p "${directory_path}"

	if [[ -z "${directory}" ]]; then
		directory="$(basename "${source_path}")"
	fi

	rootfs_files_create "${source_path}"
	rootfs_files_date "${source_path}"

	local tar_options=(
		--create
		--xz
		--file="${rootfs_path}"
		--files-from="${tarfiles_path}"
		--no-recursion
		--null
		--owner=0
		--group=0
		--numeric-owner
	)

	(
		cd "${source_path}"
		execute_root tar "${tar_options[@]}"
	)

	execute_root chmod 644 "${rootfs_path}"
	execute_root chown "${USER}:${USER}" "${rootfs_path}"
}

requirements() {
	local requirement
	local requirement_path

	for requirement in "$@"
	do
		requirement_path=$( which "$requirement" || true )

		if [ -z "$requirement_path" ]
		then
			printf '%s\n' "Missing requirement: $requirement" >&2
			exit 1
		fi
	done
}

requirements_root() {
	local requirement
	local requirement_path

	for requirement in "$@"
	do
		# We need to keep stdout output to show the command.
		requirement_path=$( execute_root which "$requirement" || true )

		if [ -z "$requirement_path" ]
		then
			printf '%s\n' "Missing requirement: $requirement" >&2
			exit 1
		fi
	done
}

arguments_concat() {
	local delimiter=$1
	shift

	local concat

	for argument in "$@"
	do
		if ! [ -z "$concat" ]
		then
			concat="$concat""$delimiter""$argument"
		else
			concat="$argument"
		fi
	done

	printf '%s\n' "$concat"
}

execute_root() {
	local sudo=$( which sudo 2> /dev/null || true )
	local arguments

	printf '%s' 'Running command as root: ' >&2
	printf '%b\n' "$*" >&2

	if ! [ -z "$sudo" ]
	then
		sudo "$@"
	else
		# Quote arguments for eval through su.
		arguments=$( printf '%q ' "$@" )
		su -c "$arguments"
	fi
}
